In the manufacture of crankshafts, the crank pins of the crankshaft must be ground to size on a grinding machine. To ensure that the grinding operation is ended as soon as a desired size is reached, it is necessary to continuously check the crank pin during the machining operation, in particular with regard to its diameter and roundness, within the scope of an in-process measurement method. EP-A-0859689 discloses a corresponding measuring device.
A measuring device is known from EP-A-1370391 which is used for in-process measurement of crank pins during a grinding operation on a grinding machine. The known measuring device has a measuring head which is connected via a rod assembly to a base body of the measuring device so as to be pivotable about a first pivot axis. The known measuring device also has a means for pivoting the measuring head in and out of the measuring position. For carrying out an in-process measurement of a crank pin, the measuring head is pivoted by the means provided for this purpose into a measuring position in which the measuring head, for example using a measuring prism, comes to rest against the crank pin to be measured. During the grinding operation the crank pin undergoes an orbital rotation about the rotational axis of the crankshaft. The grinding wheel remains in contact with the crank pin, and for this purpose is movably supported radially with respect to the rotational axis of the crankshaft. To ensure that measurements may be carried out at the crank pin during the entire grinding operation, the measuring head follows the motions of the crank pin. For this purpose the base body of the measuring device is connected to a base body of the grinding machine, so that during the grinding operation the measuring device is moved in the radial direction of the crankshaft, synchronously with the grinding wheel of the grinding machine.
A measuring device of this type is known which has a base body, and a measuring head which may be moved between a rest position and a measuring position. The known measuring device also has a means for moving the measuring head from the rest position into the measuring position, whereby this means may be formed in particular by a means for pivoting the measuring head. The known measuring device also has a stop for limiting the motion of the measuring head from the rest position into the measuring position.